1. Field of the Invention
With reference to the classification of art as established in the U.S. Patent Office, this invention pertains to the general Class of "Winding and Reeling" (Class 242) and more particularly to the subclass of "contractible or expansible -- with inflatable means" (subclass 72B).
2. Description of the Prior Art
Expanding chucks and mandrels are, of course, well known in the art and in particular expanding mandrels or chucks which use hydraulic fluid or air to expand segments. Such a device is particularly shown and described in my U.S. Pat. No. 3,825,167 and in U.S. Pat. application Ser. No. 488,160 as filed on July 12, 1974 and now U.S. Pat. No. 3,917,187. Many expanding mandrels and chucks have the expanding leaf members retained by one or more fixed members. In my application Ser. No. 488,160, above identified, an attempt has been made and actually has been achieved in which the complete peripheral surface providing the carrying and driving portion of the expanding mandrel or chuck are outwardly and inwardly moving leaf segments longitudinally arranged. However, it has been found that leaf segments so arranged usually occupy either one-third or one-fourth of the circumference and, hence, are limited in the range of sizes for the mandrels used. For most mandrels the leaf segments must be manufactured to accommodate a particular size of mandrel of chuck. Such a design, although effective, has required an extensive outlay of material since a multiplicity of sizes is required to service industry. In the expanding mandrel or chuck shown in Ser. No. 488,160 it is also required that in order to derive an equal pressure on the expanding leafs the tube must be helically wound. In the present invention both a helically wound tubing or a longitudinally arranged tubing may be utilized. The interlocked, longitudinal segments which are a series of like metal extrusions are simply cut to length from a long extrusion length. The contemplated longitudinal segments, as reduced to practice, have a pitch length of one-sixteenth pi, one eighth pi or one-quarter pi. In this way mandrel diameters up to one inch may be provided in increments of 1/16 inch on diameter by using segments which are one-sixteenth of pi (0.196 inches). Mandrels from one inch to two and seven-eighths diameter employing segments that are one-eighth pi (0.393 inches and from three inches up diameter, one-quarter pi segments (0.785 inches). As formed, leaf segments have one longitudinal edge formed as a tongue with an enlarged rounded end. The other edge is formed with an arcuate T-groove. The undersurface portion of each of the longitudinal segments is provided with two longitudinal grooves in which protruding portions of rubber strips are fitted. These mounted rubber strips act as tension members and also as a chafing strip and resilient cushion for protecting the tubing which is mounted in the grooves as the expanded tubing is pushed outwardly against the leaf members.